Over recent years, for example, for mobile communication base stations or as antenna devices for Wi-Fi communication equipment, to ensure a communication capacity, orthogonal dual polarization wave antennas and orthogonal dual polarization antenna arrays capable of performing MIMO (multi-input-multi-output) communication by polarization wave diversity have been put into practical use.
Many of the antennas are realized by two antenna elements disposed substantially vertically, and an antenna array is also realized by arraying antenna elements disposed in such a manner. Enhancement of a degree of integration of two elements has been desired for size reduction of a device.
Orthogonal dual polarization wave antennas are disclosed in, for example, Patent Literatures 1 to 3 (PTL1 to PTL3). In the orthogonal dual polarization wave antennas disclosed in these PTLs, techniques for realizing an orthogonal dual polarization wave antenna using a dipole antenna are disclosed.